Two track multiple element magnetic head

ABSTRACT

A multiple-element magnetic head comprising a plurality of magnetic head half-members arranged in face to face relation with each other at opposing end surfaces, with magnetic gaps being formed between them. Such magnetic head half-members are each made by holding non-magnetic members of substantially inverted Ushape each including a horizontal portion and oppositely disposed vertical portions between magnetic members identical in shape and configuration with said non-magnetic members, holding the assembly between substantially U-shaped cores including a horizontal portion and oppositely disposed vertical portions, cutting off said horizontal portions of said non-magnetic members and said magnetic members while leaving said oppositely disposed vertical portions, and grinding end surfaces of said oppositely disposed vertical portions of the non-magnetic members and magnetic members at which the horizontal portions have been cut off so that said end surfaces may be flush with end surfaces of the cores which are to be positioned in face to face relation with end surfaces of cores of the other magnetic head halfmember.

United States Patent Suzuki et a]. [4 1 July 25, 1972 [54] TWO TRACKMULTIPLE ELEIVIENT 3,249,928 5/1966 Curtis et al ..179/l00.2 C MAGNETICHEAD 3,354,540 11/1967 Duinker ..340/174.1 F 2,933,565 4/1960 Neumann..l79/100.2 C [72] Inventors: Toslu Suzuki, Kamakura; Tsutomu Nishijima,Yokohama, both of Japan Primary Examiner-Bernard Konick [73] Assignee:Victor Company of Japan, Limited, Assismm Examiner-Robe" PP Yokohama,Japan Att0rneyStevens, Davis, Miller & Mosher [22] Filed: July 22, 1970[57 ABSTRACT [21] APPL 57,155 A multiple-element magnetic headcomprising a plurality of magnetic head half-members arranged in face toface relation Related Apphcafion Data with each other at opposing endsurfaces, with magnetic gaps [62] Division of Ser. No. 780,393, Dec. 2,1968, Pat. No. being formed between them. Such magnetic head half-mem-3,545,077. bers are each made by holding non-magnetic members ofsubstantially inverted U-shape each including a horizontal portion [30]Foreign Application Priority Data and oppositely disposed verticalportions between magnetic members identical in shape and configurationwith said non- Dec. 4, 1967 Japan ..42/77390 magnetic members holdingthe assembly between Substam tially U-shaped cores including ahorizontal portion and op- [gf] US. Cl. positely disposed verticalportions cutting off Said horizontal Feld ofse h I100 2 1 portions ofsaid non-magnetic members and said magnetic I 346/74M members whileleaving said oppositely disposed vertical portions, and grinding endsurfaces of said oppositely disposed vertical portions of thenon-magnetic members and magnetic [56] References cued members at whichthe horizontal portions have been cut off so UNITED STATES PATENTS thatsaid end surfaces may be flush with end surfaces of the cores which areto be positioned in face to face relation with 2923,779 2/1960Namenyl'Katz -340/174-1 F end surfaces of cores of the other magnetichead half-member. 2,928,079 3/1960 NcNutt.... ...340/l74.1 F 2,717,9289/1955 Nordyke "179/1002 C 4 Claims, 8 Drawing Figures PATENIEDJIMS m2SHEET 1 BF 3 INVENTORS TOSHI SUZUKI TSUTOMU NISHIJIMA By Steve/13,Qqw's, Miller 8 Mos/1e! TWO TRACK MULTIPLE ELEMENT MAGNETIC HEAD Theapplication is a division of U.S. application Ser. No. 780,393 filedDec. 2, 1968, now U.S. Pat. No. 3,545,077 granted Dec. 8, 1970.

The present invention relates to multiple-elements magnetic heads ingeneral, and in particular the invention deals with a multiple-elementmagnetic head adapted for use with multichannel tape cartridge playersand a method of making same.

A principal object of this invention is to provide a multipleelementmagnetic head which can be readily made in a short interval of time andyet has good properties.

Another object of the invention is to provide a multiple-elementmagnetic head which permits to eliminate or reduce cross talk withrespect to a given track width.

Still another object of the invention is to provide a method of making amultiple-element magnetic head which permits to fabricate an integralmultiple-element magnetic head by first forming a plurality of magnetichead half-members, grinding surfaces of such half-members which are tobe disposed in face to face relation with each other in assembling, andthen arranging such half-members in face to face relation with eachother at said ground surfaces.

Additional objects and advantages of the invention will become apparentfrom consideration of the description set forth hereunder whenconsidered in conjunction with the accompanying drawings, in which:

FIGS. 1(A), 1(B), 1(C) and 1(D) are perspective Views of variouscomponent parts of one embodiment of a multiple-element magnetic headaccording to this invention:

FIGS. 2 to 6 are perspective views showing one example of variousoperational steps of making a multiple-element magnetic head accordingto this invention;

FIG. 7 is a perspective view of essential portions of a multiple-elementmagnetic head according to this invention, with certain parts beingomitted; and

FIG. 8 is a perspective view, with certain parts being cut out, of acompleted multiple-element magnetic head according to this invention.

A multiple-element magnetic head for multichanncls embodying the presentinvention will now be explained with reference to the drawings.

FIGS. 1(A), 1(B), 1(C) and 1(D) show component parts of one embodimentof a multiple-element magnetic head according to this invention. FIG.1(A) shows a magnetic plate of substantially inverted U-shape 14 formedas of 78 percent permalloy (0.09 mm thick) and including a horizontalportion 12 and oppositely disposed vertical portions 11 and 13. Thevertical portions 1 1 and 13 are formed with connecting portions 15 and16 respectively which constitute the upper parts of the vertical memberscontiguous with the horizontal portion 12 and have a smaller thicknessthan other parts of the vertical portions so as to facilitate cuttingtherethrough as subsequently to be described. FIG. 1(B) shows asubstantially U- shaped core formed by bonding a plurality of 78 percentpermalloy plates (0.09 mm thick), for example, with a bonding agent,such as Araldite XV, for example, to provide a laminate and including ahorizontal portion 18 and oppositely disposed vertical portions 17 and19. A coil (20 in diameter) is wound on the horizontal member 18 inconvolutions forming three layers in close contact with one another assubsequently to be described. Shown in FIG. 1(C) is a shield plate 21rectangular in shape and made as of 78 percent permalloy (0.1 mm thick),said shield plate 21 being formed with a cutout 22 on one lateral edgethereof for passing lead wires for the coils therethrough. Shown in FIG.1(D) is a non-magnetic plate 26 of substantially inverted U-shapeidentical in shape and configuration with said magnetic plate 14 ofsubstantially inverted U-shape 14 made as of phosphor bronze (0.09 mmthick) and including a horizontal portion 24 and oppositely disposedvertical portions 23 and 25. The vertical portions 23 and 25 are formedwith connecting portions 27 and 28 respectively which constitute theupper parts of the vertical portions contiguous with the horizontalportion 24 and have a smaller thickness than other parts of the verticalportion so as to facilitate cutting therethrough as subsequently to bedescribed.

FIGS. 2 to 6 show one embodiment of a method of making amultiple-element magnetic head according to this invention.

FIG. 2 shows in an exploded view the arrangement of members to belaminated. In FIG. 2, one rectangular shield plate 21 is disposed in thecenter and two non-magnetic plates 26 of substantially inverted U-shapeeach including the horizontal portions 24 and oppositely disposedvertical portions 23 and 25 are each arranged on opposite sides of saidshield plate. Two magnetic plates 14 of substantially inverted U-shapeidentical with said non-magnetic plates 26 and each including thehorizontal portion 12 and oppositely disposed vertical portions 11 and13 are each arranged on the opposite sides of said non-magnetic plates26.

The shield plate 21, two non-magnetic plates 26 of substantiallyinverted U-shape and two magnetic plates 14 of substantially invertedU-shape arranged as aforementioned are bonded to one another withAronalpha which is a monomer of alphacyanoacrylate, for example, toprovide a laminate of integral structure which is generally designated29 in FIG. 3.

Then, the two substantially U-shaped cores 20 each having a coil 30wound on the horizontal portion 18 are arranged on opposite sides of thelaminate 29.

Then, the laminate 29 is held by the two substantially U- shaped cores20 on opposite sides, and they are bonded together with a bonding agent,such as said Aronalpha, for example, to form another laminate ofintegral structure.

After said another laminate of integral structure is made, thehorizontal portions 12 and 24 of the magnetic plates 14 of substantiallyinverted U-shape and non-magnetic plates 26 of substantially invertedU-shape respectively are cut off from the rest of the plates at theconnecting portions 15, 16 and 27, as shown in FIG. 5.

Then, end surfaces of the connecting portions 15, 16, 27, and 28 atwhich the horizontal portions are cut off are ground so that they may beflush with end surfaces 31 and 32 of the oppositely disposed verticalportions which are to be disposed in face to face relation with eachother when assembled. At the same time, comers 33 of the shield plate 21are rounded by grinding.

A magnetic head half-member is formed by the steps described above.

Two magnetic head half-members formed by the process explained above arearranged in face to face relation with each other at their respectiveopposing end surfaces with magnetic gaps 34 and 35 being disposedtherebetween as shown in FIG. 6 to provide an assembled multiple-elementmagnetic head unit.

In the multiple-element magnetic head unit shown in FIG. 6, a gap formedbetween the substantially U-shaped core 20 and the magnetic plate 14having its horizontal portion 12 cut off which are arranged on one sideof one magnetic head halfmember and the substantially U-shaped core 20and the magnetic plate 14 having its horizontal portion 12 cut off whichare arranged on one side of the other magnetic head halfmember disposedin face to face relation with said one magnetic head half-memberconstitutes the magnetic head gap 34 of one element having a widthproportionate to the thickness of said substantially U-shaped cores 20and said magnetic plates 14. Similarly, a gap formed between thesubstantially U- shaped core 20 and the magnetic plate 14 having itshorizontal portion 14 cut off which are arranged on the other side ofsaid one magnetic head half-member and the substantially U- shaped core20 and the magnetic plate 14 having its horizontal portion 12 cut offwhich are arranged on the other side of said the other magnetic headhalf-member disposed in face to face relation with said one magnetichead half-member constitutes the magnetic head gap 35 of the otherelement.

Spaces 36 which have a width corresponding to the thickness of themagnetic plate 14 plus the thickness of the non-magnetic plate 26 aredefined by the horizontal portions 18 of the substantially U-shapedcores 20, the shield plates 21, the vertical members 1 l, 23 and thevertical members 13, 25.

Then, surfaces of the cores 20, the non-magnetic plates 26, the magneticplates 14, and the shield plates 21 which are operatively brought intocontact with a magnetic tape are ground.

The multiple-element magnetic head unit made as shown in FIG. 6 is thenfitted in a groove 38 formed in a holder 37, and Epikote resin, forexample, is poured in said holder 37 so as to fix the multiple-elementmagnetic head unit in place in the holder. Thus, the multiple-elementmagnetic head is completed.

FIGS. 7 and 8 show the completed multiple-element magnetic head as fixedin place in the holder. The holder 37 has a plurality of terminals 39attached thereto to which are connected initial portions and endportions of said coils 30 wound on the cores 20.

From the foregoing description, it will be appreciated that in themultiple-element magnetic head embodying this invention, the width of atrack recorded on a magnetic tape is equal to the width of the magneticgap which is equal to the thickness of the magnetic plate 14 plus thethickness of the core 20. Since the coils 30 are wound only on the cores20, however, the path of a turn of coil can be reduced, because coilwindings are small in size as compared to the width of the magnetic gapeven if a large number of turns of coil are formed by using a finewires. This is conducive to reduced D.C. resistance in the coil andincreased inductance. Also, the coils 30 wound on the cores 20 arespaced apart from each other, so that cross talk with respect to a giventrack width can be reduced or eliminated.

v The magnetic plates 14 and non-magnetic plates 26 defining the space36 between their forward ends and rearward ends have their forward endsand rearward ends integrally connected together by the intermediateportions prior to being made into a magnetic head half-member. Thispermits to readily arrange, in assembling, the end surfaces of theforward end portions adapted to come into contact with a magnetic tapeand the end surfaces of the core adapted to come into contact with amagnetic tape in one vertical plane.

While the present invention has been shown and described with referenceto a preferred embodiment thereof, it is to be understood that theinvention is not to be limited to the precise form of the embodiment,and that many changes and modifications may be made therein withoutdeparting from the spirit and scope of the invention and the appendedclaims should therefore be interpreted to cover such changes andmodifications.

What is claimed is:

l. A two track multiple-element magnetic head comprising first andsecond magnetic head half-members arranged in face-to-face relation attheir opposing end surface, each of said magnetic head half-membersincluding a rectangular shield, non-magnetic members bonded to both topand bottom portions of said shield and on respective opposite sides ofsaid shield, magnetic members corresponding in shape and configurationto said non-magnetic members and bonded to respective outer sides ofsaid non-magnetic members, said magnetic members being coplanar andhaving opposing parallel aligned faces, substantially U-shaped coresbonded to respective outer sides of said magnetic members and formedwith a horizontal portion and oppositely disposed vertical portions, thecores comprising each of said magnetic head half members being coplanarand having opposing parallel aligned faces, and coils wound onrespective horizontal portions of said cores, the opposing parallelaligned faces of said magnetic members and said cores forming magneticgaps.

2. A two track multiple-element magnetic head as claimed in claim 1 inwhich a gap formed between the core and the magnetic member arranged onone side of said first magnetic head half-member and the core and themagnetic member arranged on one side of said second magnetic headhalf-member diaslposed in face to face relation with said first magnetichead h -member constitutes a magnetic head gap of one element having awidth corresponding to the thickness of the core plus the thickness ofthe magnetic member, and a gap formed between the core and the magneticmember arranged on the other side of said first magnetic headhalf-member and the core and the magnetic member arranged on the otherside of said second magnetic head half-member disposed in face to facerelation with said first magnetic head half-member further constitutes amagnetic head gap of another element having a width corresponding to thethickness of the the core plus the thickness of the magnetic member.

3. A two track multiple-element magnetic head comprising first andsecond magnetic head half-members arranged in face-to-face relation attheir opposing end surfaces, each of said magnetic head half-membersincluding a rectangular shield, non-magnetic members bonded to both topand bottom portion of said shield and on respective opposite sides ofsaid shield, magnetic members corresponding in shape and configurationto said non-magnetic members and bonded to respective outer sides ofsaid non-magnetic members, said magnetic members being coplanar andhaving opposing parallel aligned faces, substantially U-shaped coresbonded to respective outer sides of said magnetic members and formedwith a horizontal portion and oppositely disposed vertical portions,said cores being coplanar and having opposing parallel aligned faces,and coils wound on respective horizontal portions of said cores, the endsurfaces of said cores, said nonmagnetic members, said magnetic membersand said shields of said first and second magnetic head half-memberswhich are adapted to come into contact with a magnetic tape beingground, the opposing parallel aligned faces of said magnetic members andsaid cores forming magnetic gaps.

4. A two track multiple-element magnetic head as claimed in claim 3 inwhich a gap formed between the core and the magnetic member arranged onone side of said first magnetic head half-member and the core and themagnetic member arranged on one side of said second magnetic headhalf-member disposed in face to face relation with said first magnetichead half-member constitutes a magnetic head gap of one element having awidth corresponding to the thickness of the core plus the thickness ofthe magnetic member, and a gap formed between the core and the magneticmember arranged on the other side of said first magnetic headhalf-member and the core and the magnetic member arranged on the otherside of said second magnetic head half-member disposed in face to facerelation with said first magnetic head half-member further constitutes amagnetic head gap of another element having a width corresponding to thethickness of the core plus the thickness of the magnetic member.

1. A two track multiple-element magnetic head comprising first andsecond magnetic head half-members arranged in face-to-face relation attheir opposing end surface, each of said magnetic head half-membersincluding a rectangular shield, non-magnetic members bonded to both topand bottom portions of said shield and on respective opposite sides ofsaid shield, magnetic members corresponding in shape and configurationto said non-magnetic members and bonded to respective outer sides ofsaid non-magnetic members, said magnetic members being coplanar andhaving opposing parallel aligned faces, substantially U-shaped coresbonded to respective outer sides of said magnetic members and formedwith a horizontal portion and oppositely disposed vertical portions, thecores comprising each of said magnetic head half members being coplanarand having opposing parallel aligned faces, and coils wound onrespective horizontal portions of said cores, the opposing parallelaligned faces of said magnetic members and said cores forming magneticgaps.
 2. A two track multiple-element magnetic head as claimed in claim1 in which a gap formed between the core and the magnetic memberarranged on one side of said first magnetic head half-member and thecore and the magnetic member arranged on one side of said secondmagnetic head half-member disposed in face to face relation with saidfirst magnetic head half-member constitutes a magnetic head gap of oneelement having a width corresponding to the thickness of the core plusthe thicknesS of the magnetic member, and a gap formed between the coreand the magnetic member arranged on the other side of said firstmagnetic head half-member and the core and the magnetic member arrangedon the other side of said second magnetic head half-member disposed inface to face relation with said first magnetic head half-member furtherconstitutes a magnetic head gap of another element having a widthcorresponding to the thickness of the the core plus the thickness of themagnetic member.
 3. A two track multiple-element magnetic headcomprising first and second magnetic head half-members arranged inface-to-face relation at their opposing end surfaces, each of saidmagnetic head half-members including a rectangular shield, non-magneticmembers bonded to both top and bottom portion of said shield and onrespective opposite sides of said shield, magnetic members correspondingin shape and configuration to said non-magnetic members and bonded torespective outer sides of said non-magnetic members, said magneticmembers being coplanar and having opposing parallel aligned faces,substantially U-shaped cores bonded to respective outer sides of saidmagnetic members and formed with a horizontal portion and oppositelydisposed vertical portions, said cores being coplanar and havingopposing parallel aligned faces, and coils wound on respectivehorizontal portions of said cores, the end surfaces of said cores, saidnon-magnetic members, said magnetic members and said shields of saidfirst and second magnetic head half-members which are adapted to comeinto contact with a magnetic tape being ground, the opposing parallelaligned faces of said magnetic members and said cores forming magneticgaps.
 4. A two track multiple-element magnetic head as claimed in claim3 in which a gap formed between the core and the magnetic memberarranged on one side of said first magnetic head half-member and thecore and the magnetic member arranged on one side of said secondmagnetic head half-member disposed in face to face relation with saidfirst magnetic head half-member constitutes a magnetic head gap of oneelement having a width corresponding to the thicknesS of the core plusthe thickness of the magnetic member, and a gap formed between the coreand the magnetic member arranged on the other side of said firstmagnetic head half-member and the core and the magnetic member arrangedon the other side of said second magnetic head half-member disposed inface to face relation with said first magnetic head half-member furtherconstitutes a magnetic head gap of another element having a widthcorresponding to the thickness of the core plus the thickness of themagnetic member.